Hi Ipsit,
QRadar stores its event records in files representing 1 minute's worth of time. At the same time that it writes out an event record file, it writes out index files for that minute for any indexed properties (one file per property). At the end of each hour, we "roll up" the minute indexes into an hourly index. The index files contain a list of each unique value for the property, and for each of those unique files, a reference to which event records in the corresponding record file contain that value.
For non-indexed properties, if the property is used in a search filter criteria, we need to read each record in each file that matches the search's time range, checking the value of the property to see if it matches the filter.
For indexed properties, we don't need to read the event record files, we just check the index and know exactly which records match the search criteria for that particular property. If a search contains criteria for multiple indexed properties, we can cross reference which event records have values which match both criteria, so again we don't need to actually scan the record files.
Cheers
Colin
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COLIN HAY
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Original Message:
Sent: Sun March 01, 2020 12:01 PM
From: Ipsit Utkarsh
Subject: Difference between indexed and non indexed property
What is the difference between indexed and non-indexed property of Qradar ? How does indexing make the search for a property faster as compared to an non-indexed property ?
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Ipsit Utkarsh
IBM Security Services
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